import java.util.LinkedList;
import java.util.Queue;

/**
 * \* Created with IntelliJ IDEA.
 * \* User: Administrator
 * \* Date: 2022/1/19
 * \* Time: 15:59
 * \* To change this template use File | Settings | File Templates.
 * \* Description:
 * \
 */

class TreeNode{
    public char val;
    public TreeNode left;
    public TreeNode right;

    public TreeNode(char val){
        this.val = val;
    }

}

public class BinayTree {
    public TreeNode creatTree(){
        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('E');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        TreeNode H = new TreeNode('H');
        A.left = B;
        A.right = C;
        B.left = D;
        B.right = E;
        C.left = F;
        C.right = G;
        E.right = H;
        return A;
    }
//前序遍历
    public void preOrder(TreeNode root){
        if(root == null) return;
        System.out.print(root.val+" ");
        preOrder(root.left);
        preOrder(root.right);
    }
    //中序遍历

    public void inOrder(TreeNode root){
        if(root == null) return;
        inOrder(root.left);
        System.out.print(root.val+" ");
        inOrder(root.right);
    }

    //后续遍历
    public void postOrder(TreeNode root){
        if(root == null) return;
        postOrder(root.left);
        postOrder(root.right);
        System.out.print(root.val+" ");
    }

    // 获取树中节点的个数
    int sum = 0;
    int size(TreeNode root){

        if(root == null) return 0;
        sum ++;
        size(root.left);
        size(root.right);
        return sum;
    }

    //求叶子节点的个数
    public int leaves;
    public int  getLeafNodeCount(TreeNode root){
        if(root == null){
            return 0;
        }
        if(root.left == null && root.right == null){
            leaves++;
        }
        getLeafNodeCount(root.left);
        getLeafNodeCount(root.right);
        return leaves;
    }

    //求第k层节点的个数
    public int getKLevelNodeCount(TreeNode root,int k){
        if (root == null) return 0;
        if (k == 1) return 1;
        return getKLevelNodeCount(root.left,k-1) + getKLevelNodeCount(root.right,k-1);
    }
    //查找节点
    static TreeNode find(TreeNode root, char val){
        if(root == null) return null;
        if(root.val == val) return root;
        TreeNode tmp = find(root.left,val);
        if(tmp != null){
            return tmp;
        }
        return find(root.right, val);
    }

    //判断一棵树是不是完全二叉树
    boolean isComplateTree(TreeNode root){
        if(root == null) return true;
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        while (!queue.isEmpty()){
            TreeNode cur = queue.poll();
            if(cur != null){
                queue.offer(cur.left);
                queue.offer(cur.right);
            } else
                break;

        }
        while (!queue.isEmpty()){
            TreeNode top = queue.peek();
            if(top != null){
                return false;
            }
            queue.poll();
        }
        return true;
    }
}
